如何在java中调用oracle函数。函数返回数字

import java.sql.*;

public class OracleFunctionExample {
    public static void main(String[] args) {
        String url = "jdbc:oracle:thin:@localhost:1521:xe";
        String username = "your_username";
        String password = "your_password";
        String functionName = "your_function_name";
        int inputParameter = 5; // 输入参数值

        try {
            Connection connection = DriverManager.getConnection(url, username, password);

            // 创建CallableStatement对象，并设置调用的函数名称和输入参数
            String query = "{ ? = call " + functionName + "(?) }";
            CallableStatement statement = connection.prepareCall(query);
            statement.registerOutParameter(1, Types.INTEGER); // 注册输出参数类型
            statement.setInt(2, inputParameter); // 设置输入参数值

            // 执行函数调用
            statement.execute();

            // 获取函数返回值
            int returnValue = statement.getInt(1);
            System.out.println("Function returned: " + returnValue);

            statement.close();
            connection.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}